Abstract: A high pressure accumulator is disclosed which includes a housing having walls defining a chamber and a piston residing in the chamber. The piston is comprised of polyphenylene sulfide and preferably includes a head portion and wall portions extending away from the head portion. The wall portions preferably include outer and inner surfaces which are oblique. Preferably the polyphenylene sulfide includes glass fibers and minerals and is formed using injection molding techniques. The material composition of the piston and its geometrical definition give it the ability to operate when exposed to the brake fluid and when exposed to operating pressures is the range of 100 bars.

Abstract: An accumulator for an anti-lock brake system includes a valve body portion defining an accumulator chamber, an accumulator piston slidably disposed within the accumulator chamber, a spring, and a cover. The accumulator chamber has a fluid inlet for connection to a source of pressurized fluid at a first end of the chamber. The chamber has a second end open to atmosphere. The accumulator piston separates the first end of the chamber from the second end of the chamber. The spring is disposed in the accumulator chamber between the piston and the second end of the chamber and biases the piston toward a first position. The cover closes the second end of the chamber and atmosphere and has micro-porous structure. The micro-porous structure is configured to block water molecules and to pass constituent molecules of air, thereby enabling air to be communicated across while preventing the intrusion of water into the chamber through the second end.